by Cheng-Yi Chiang

[permalink] [raw]

Subject: Re: [alsa-devel] [PATCH 3/3] ASoC: cros_ec_codec: Add codec driver for Cros EC

On Thu, Nov 29, 2018 at 8:42 PM Enric Balletbo Serra
<[email protected]> wrote:
>
> Hi Cheng-Yi
>
> Many thanks for the patch. I am not really an ASoC expert, so my
> comments are more based on the feedback for other cros-ec drivers. So,
> various nits and few comments below.
>

Hi Enric,
Thank you for the review and sorry for the late response.
It took me a while to clean up this patches. I have addressed all your
comments in v2.

> The first question I'd like to ask is if there is any EC_FEATURE that
> tells you that the cros-ec has the codec. And second (if you can
> answer), could you tell me which device you used to test this?

Yes, there is an EC_FEATURE = 38 on EC side, which was added in this
CL: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1192702
But on kernel side for the board I am using, it is not used because
the presence of EC is from entry in DTS.
This is different from MFD ec_device_probe path in drivers/mfd/cros_ec_dev.c.
The device I am using to test this codec driver is Qualcomm SDM845 board.

>
> Missatge de Cheng-Yi Chiang <[email protected]> del dia dt., 27 de
> nov. 2018 a les 13:02:
> >
> > Add a codec driver to control ChromeOS EC codec.
> >
> > Use EC Host command to enable/disable I2S recording and control other
> > configurations.
> >
> > Signed-off-by: Cheng-Yi Chiang <[email protected]>
> > ---
> > MAINTAINERS | 1 +
> > sound/soc/codecs/Kconfig | 8 +
> > sound/soc/codecs/Makefile | 2 +
> > sound/soc/codecs/cros_ec_codec.c | 499 +++++++++++++++++++++++++++++++
> > sound/soc/codecs/cros_ec_codec.h | 33 ++
> > 5 files changed, 543 insertions(+)
> > create mode 100644 sound/soc/codecs/cros_ec_codec.c
> > create mode 100644 sound/soc/codecs/cros_ec_codec.h
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 5cf8ab296cc61..f1999ef19d1cc 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -3556,6 +3556,7 @@ CHROME EC CODEC DRIVER
>
> Trying to be coherent with names s/CHROME/CHROMEOS/
>

Fixed in v2.

> > M: Cheng-Yi Chiang <[email protected]>
>
> Do you mind adding me as a reviewer? I am interested in review all the
> cros-ec related patches.
>
> R: Enric Balletbo i Serra <[email protected]>
>

No problem.
Fixed in v2.

> > S: Maintained
> > F: Documentation/devicetree/bindings/sound/google,cros-ec-codec.txt
> > +F: sound/soc/codecs/cros_ec_codec.*
> >
> > CIRRUS LOGIC AUDIO CODEC DRIVERS
> > M: Brian Austin <[email protected]>
> > diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
> > index efb095dbcd714..3e3e9294c0259 100644
> > --- a/sound/soc/codecs/Kconfig
> > +++ b/sound/soc/codecs/Kconfig
> > @@ -49,6 +49,7 @@ config SND_SOC_ALL_CODECS
> > select SND_SOC_BT_SCO
> > select SND_SOC_BD28623
> > select SND_SOC_CQ0093VC
> > + select SND_SOC_CROS_EC_CODEC
> > select SND_SOC_CS35L32 if I2C
> > select SND_SOC_CS35L33 if I2C
> > select SND_SOC_CS35L34 if I2C
> > @@ -445,6 +446,13 @@ config SND_SOC_CPCAP
> > config SND_SOC_CQ0093VC
> > tristate
> >
> > +config SND_SOC_CROS_EC_CODEC
> > + tristate "codec driver for Cros EC"
>
> s/Cros EC/ChromeOS EC
>

Fixed in v2.

> > + depends on MFD_CROS_EC
> > + help
> > + If you say yes here you will get support for the
> > + Chrome OS Embedded Controller's Audio Codec.
>
> nit: s/Chrome OS/ChromeOS/
>
> Based on past discussions It's not really clear if you should use
> Chrome OS or ChromeOS. Personally, I like the second version which is
> more used but I don't mind which one you use, but don't mix Chrome OS
> and ChromeOS, use the same form for in your patch. I'll point you
> where you used "Chrome OS" in this review.
>

I should use ChromeOS.
Fixed in v2.

> > +
> > config SND_SOC_CS35L32
> > tristate "Cirrus Logic CS35L32 CODEC"
> > depends on I2C
> > diff --git a/sound/soc/codecs/Makefile b/sound/soc/codecs/Makefile
> > index 7ae7c85e8219f..ff05c260c5776 100644
> > --- a/sound/soc/codecs/Makefile
> > +++ b/sound/soc/codecs/Makefile
> > @@ -41,6 +41,7 @@ snd-soc-bd28623-objs := bd28623.o
> > snd-soc-bt-sco-objs := bt-sco.o
> > snd-soc-cpcap-objs := cpcap.o
> > snd-soc-cq93vc-objs := cq93vc.o
> > +snd-soc-cros-ec-codec-objs := cros_ec_codec.o
> > snd-soc-cs35l32-objs := cs35l32.o
> > snd-soc-cs35l33-objs := cs35l33.o
> > snd-soc-cs35l34-objs := cs35l34.o
> > @@ -301,6 +302,7 @@ obj-$(CONFIG_SND_SOC_BD28623) += snd-soc-bd28623.o
> > obj-$(CONFIG_SND_SOC_BT_SCO) += snd-soc-bt-sco.o
> > obj-$(CONFIG_SND_SOC_CQ0093VC) += snd-soc-cq93vc.o
> > obj-$(CONFIG_SND_SOC_CPCAP) += snd-soc-cpcap.o
> > +obj-$(CONFIG_SND_SOC_CROS_EC_CODEC) += snd-soc-cros-ec-codec.o
> > obj-$(CONFIG_SND_SOC_CS35L32) += snd-soc-cs35l32.o
> > obj-$(CONFIG_SND_SOC_CS35L33) += snd-soc-cs35l33.o
> > obj-$(CONFIG_SND_SOC_CS35L34) += snd-soc-cs35l34.o
> > diff --git a/sound/soc/codecs/cros_ec_codec.c b/sound/soc/codecs/cros_ec_codec.c
> > new file mode 100644
> > index 0000000000000..e24174c11a7de
> > --- /dev/null
> > +++ b/sound/soc/codecs/cros_ec_codec.c
> > @@ -0,0 +1,499 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * cros_ec_codec - Driver for Chrome OS Embedded Controller codec.
>
> nit: remove "cros_ec_code -" just put the description here. If for
> some weird reason the file changes the name this will be probably
> incorrect and doesn't apport anything.
> nit: s/Chrome OS/ChromeOS/
>

Fixed in v2.

> > + *
> > + * Copyright 2018 Google, Inc
> > + *
> > + * This software is licensed under the terms of the GNU General Public
> > + * License version 2, as published by the Free Software Foundation, and
> > + * may be copied, distributed, and modified under those terms.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + *
>
> You can remove LICENSE boilerplate, is inherent to the SPDX-License-Identifier.
>

Fixed in v2.

> > + * This driver uses the cros-ec interface to communicate with the Chrome OS
>
> nit: s/Chrome OS/ChromeOS/
>

Fixed in v2.

> > + * EC for audio function.
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/device.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mfd/cros_ec.h>
> > +#include <linux/mfd/cros_ec_commands.h>
> > +#include <linux/module.h>
> > +#include <sound/pcm.h>
> > +#include <sound/pcm_params.h>
> > +#include <sound/soc.h>
> > +#include <sound/tlv.h>
> > +#include <linux/platform_device.h>
>
> nit: I like see alphabetical order here
>

Fixed in v2.

> > +
> > +#include "cros_ec_codec.h"
> > +
> > +#define MAX_GAIN 43
> > +
> > +#define DRV_NAME "cros-ec-codec"
> > +
> > +static const DECLARE_TLV_DB_SCALE(ec_mic_gain_tlv, 0, 100, 0);
> > +/*
> > + * Wrapper for EC command.
> > + */
> > +static int ec_command(struct snd_soc_component *component, int version,
> > + int command, uint8_t *outdata, int outsize,
> > + uint8_t *indata, int insize)
>
> nit: s/uint8_t/u8/ checkpatch --strict ? Will spot more format issues
> in this patch. I'm going to add some of these to this review as a nit.
>

Thank you for the reminder. Using --strict is better.
Fixed in v2.

> > +{
> > + struct cros_ec_codec_data *codec_data = snd_soc_component_get_drvdata(
>
> nit: Lines should not end with a '('
>

Fixed in v2.

> > + component);
> > + struct cros_ec_device *ec_device = codec_data->ec_device;
> > + struct cros_ec_command *msg;
> > + int ret;
> > +
> > + msg = kzalloc(sizeof(*msg) + max(insize, outsize), GFP_KERNEL);
> > + if (!msg)
> > + return -ENOMEM;
> > +
> > + msg->version = version;
> > + msg->command = command;
> > + msg->outsize = outsize;
> > + msg->insize = insize;
> > +
> > + if (outsize)
> > + memcpy(msg->data, outdata, outsize);
> > +
> > + ret = cros_ec_cmd_xfer_status(ec_device, msg);
> > + if (ret > 0 && insize)
> > + memcpy(indata, msg->data, insize);
> > +
> > + kfree(msg);
> > + return ret;
> > +}
> > +
> > +static int set_i2s_config(struct snd_soc_component *component,
> > + enum ec_i2s_config i2s_config)
>
> nit: Alignment should match open parenthesis
>

Fixed in v2.

> > +{
> > + struct ec_param_codec_i2s param;
> > + int ret;
> > +
> > + dev_dbg(component->dev, "%s set I2S format to %u\n", __func__,
> > + i2s_config);
> > +
> > + param.cmd = EC_CODEC_I2S_SET_CONFIG;
> > + param.i2s_config = i2s_config;
> > +
> > + ret = ec_command(component, 0, EC_CMD_CODEC_I2S,
> > + (uint8_t *)&param, sizeof(param),
>
> nit: Prefer kernel type 'u8' over 'uint8_t'
>

Fixed in v2.

> > + NULL, 0);
> > + if (ret < 0) {
> > + dev_err(component->dev,
> > + "set I2S format to %u command returned 0x%x\n",
> > + i2s_config, ret);
> > + return -EINVAL;
> > + }
> > + return 0;
> > +}
> > +
> > +static int cros_ec_i2s_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
> > +{
> > + struct snd_soc_component *component = dai->component;
> > + enum ec_i2s_config i2s_config;
> > +
> > + dev_dbg(component->dev, "%s enter\n", __func__);
>
> Entry and exit debugging log are not really useful, and you can use
> kernel trace tools to check that, so better remove it.
>

Fixed in v2.

> > +
> > + switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
> > + case SND_SOC_DAIFMT_CBS_CFS:
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
> > + case SND_SOC_DAIFMT_NB_NF:
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
> > + case SND_SOC_DAIFMT_I2S:
> > + i2s_config = EC_DAI_FMT_I2S;
> > + break;
> > +
> > + case SND_SOC_DAIFMT_RIGHT_J:
> > + i2s_config = EC_DAI_FMT_RIGHT_J;
> > + break;
> > +
> > + case SND_SOC_DAIFMT_LEFT_J:
> > + i2s_config = EC_DAI_FMT_LEFT_J;
> > + break;
> > +
> > + case SND_SOC_DAIFMT_DSP_A:
> > + i2s_config = EC_DAI_FMT_PCM_A;
> > + break;
> > +
> > + case SND_SOC_DAIFMT_DSP_B:
> > + i2s_config = EC_DAI_FMT_PCM_B;
> > + break;
> > +
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + set_i2s_config(component, i2s_config);
> > +
> > + dev_dbg(component->dev, "%s set I2S DAI format\n", __func__);
>
> Remove this debug message it is only used to trace the exit of the function.
>

Fixed in v2.

> > +
> > + return 0;
> > +}
> > +
> > +static int set_i2s_sample_depth(struct snd_soc_component *component,
> > + enum ec_sample_depth_value depth)
> > +{
> > + struct ec_param_codec_i2s param;
> > + int ret;
> > +
> > + dev_dbg(component->dev, "%s set depth to %u\n", __func__, depth);
> > +
> > + param.cmd = EC_CODEC_SET_SAMPLE_DEPTH;
> > + param.depth = depth;
> > +
> > + ret = ec_command(component, 0, EC_CMD_CODEC_I2S,
> > + (uint8_t *)&param, sizeof(param),
> > + NULL, 0);
> > + if (ret < 0) {
> > + dev_err(component->dev, "I2S sample depth %u returned 0x%x\n",
> > + depth, ret);
> > + return -EINVAL;
> > + }
> > + return 0;
> > +}
> > +
> > +static int set_bclk(struct snd_soc_component *component, uint32_t bclk)
> > +{
> > + struct ec_param_codec_i2s param;
> > + int ret;
> > +
> > + dev_dbg(component->dev, "%s set i2s bclk to %u\n", __func__, bclk);
> > +
> > + param.cmd = EC_CODEC_I2S_SET_BCLK;
> > + param.bclk = bclk;
> > +
> > + ret = ec_command(component, 0, EC_CMD_CODEC_I2S,
> > + (uint8_t *)&param, sizeof(param),
> > + NULL, 0);
> > + if (ret < 0) {
> > + dev_err(component->dev, "I2S set bclk %u command returned 0x%x\n",
> > + bclk, ret);
> > + return -EINVAL;
> > + }
> > + return 0;
> > +}
> > +
> > +static int cros_ec_i2s_hw_params(struct snd_pcm_substream *substream,
> > + struct snd_pcm_hw_params *params, struct snd_soc_dai *dai)
> > +{
> > + struct snd_soc_component *component = dai->component;
> > + int frame_size;
> > + unsigned int rate, bclk;
> > + int ret;
> > +
> > + frame_size = snd_soc_params_to_frame_size(params);
> > + if (frame_size < 0) {
> > + dev_err(component->dev, "Unsupported frame size: %d\n",
> > + frame_size);
> > + return -EINVAL;
> > + }
> > +
> > + rate = params_rate(params);
> > + if (rate != 48000) {
> > + dev_err(component->dev, "Unsupported rate\n");
> > + return -EINVAL;
> > + }
> > +
> > + switch (params_format(params)) {
> > + case SNDRV_PCM_FORMAT_S16_LE:
> > + ret = set_i2s_sample_depth(component, EC_CODEC_SAMPLE_DEPTH_16);
> > + break;
> > + case SNDRV_PCM_FORMAT_S24_LE:
> > + ret = set_i2s_sample_depth(component, EC_CODEC_SAMPLE_DEPTH_24);
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + if (ret)
> > + return ret;
> > +
> > + bclk = snd_soc_params_to_bclk(params);
> > + ret = set_bclk(component, bclk);
> > +
> > + return ret;
> > +}
> > +
> > +static const struct snd_soc_dai_ops cros_ec_i2s_dai_ops = {
> > + .hw_params = cros_ec_i2s_hw_params,
> > + .set_fmt = cros_ec_i2s_set_dai_fmt,
> > +};
> > +
> > +struct snd_soc_dai_driver cros_ec_dai[] = {
> > + {
> > + .name = "cros_ec_codec I2S",
> > + .id = 0,
> > + .capture = {
> > + .stream_name = "I2S Capture",
> > + .channels_min = 2,
> > + .channels_max = 2,
> > + .rates = SNDRV_PCM_RATE_48000,
> > + .formats = SNDRV_PCM_FMTBIT_S16_LE |
> > + SNDRV_PCM_FMTBIT_S24_LE,
> > + },
> > + .ops = &cros_ec_i2s_dai_ops,
> > + }
> > +};
> > +
> > +static int get_ec_mic_gain(struct snd_soc_component *component,
> > + uint8_t *left, uint8_t *right)
> > +{
> > + struct ec_param_codec_i2s param;
> > + struct ec_response_codec_gain resp;
> > + int ret;
> > +
> > + dev_dbg(component->dev, "%s get mic gain\n", __func__);
>
> Remove the trace.
>

Fixed in v2.

> > +
> > + param.cmd = EC_CODEC_GET_GAIN;
> > +
> > + ret = ec_command(component, 0, EC_CMD_CODEC_I2S,
> > + (uint8_t *)&param, sizeof(param),
> > + (uint8_t *)&resp, sizeof(resp));
> > + if (ret < 0) {
> > + dev_err(component->dev, "I2S get gain command returned 0x%x\n",
> > + ret);
> > + return -EINVAL;
> > + }
> > +
> > + *left = resp.left;
> > + *right = resp.right;
> > +
> > + dev_dbg(component->dev, "%s get mic gain %u, %u\n", __func__,
> > + *left, *right);
> > +
> > + return 0;
> > +}
> > +
> > +static int mic_gain_get(struct snd_kcontrol *kcontrol,
> > + struct snd_ctl_elem_value *ucontrol)
> > +{
> > + struct snd_soc_component *component = snd_soc_kcontrol_component(
> > + kcontrol);
> > + uint8_t left, right;
> > + int ret;
> > +
> > + ret = get_ec_mic_gain(component, &left, &right);
> > +
> > + if (ret)
> > + return ret;
> > +
> > + ucontrol->value.integer.value[0] = left;
> > + ucontrol->value.integer.value[1] = right;
> > +
> > + return 0;
> > +}
> > +
> > +static int set_ec_mic_gain(struct snd_soc_component *component,
> > + uint8_t left, uint8_t right)
> > +{
> > + struct ec_param_codec_i2s param;
> > + int ret;
> > +
> > + dev_dbg(component->dev, "%s set mic gain to %u, %u\n",
> > + __func__, left, right);
> > +
> > + param.cmd = EC_CODEC_SET_GAIN;
> > + param.gain.left = left;
> > + param.gain.right = right;
> > +
> > + ret = ec_command(component, 0, EC_CMD_CODEC_I2S,
> > + (uint8_t *)&param, sizeof(param),
> > + NULL, 0);
> > + if (ret < 0) {
> > + dev_err(component->dev, "I2S set gain command returned 0x%x\n",
>
> %d ? Doesn't make more sense print the decimal format here?
> I know that other cros_ec drivers do this, is something to fix I guess.
>

Fixed in v2. Also fixed in other places.

> > + ret);
> > + return -EINVAL;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int mic_gain_put(struct snd_kcontrol *kcontrol,
> > + struct snd_ctl_elem_value *ucontrol)
> > +{
> > + struct snd_soc_component *component = snd_soc_kcontrol_component(
> > + kcontrol);
> > + int left = ucontrol->value.integer.value[0];
> > + int right = ucontrol->value.integer.value[1];
> > + int ret;
> > +
> > + if (left > MAX_GAIN || right > MAX_GAIN)
> > + return -EINVAL;
> > +
> > + ret = set_ec_mic_gain(component, (uint8_t)left, (uint8_t)right);
> > +
> > + if (ret)
> > + return ret;
> > +
> > + return 0;
> > +}
> > +
> > +static const struct snd_kcontrol_new cros_ec_snd_controls[] = {
> > + SOC_DOUBLE_EXT_TLV("EC Mic Gain", SND_SOC_NOPM, SND_SOC_NOPM, 0, 43, 0,
> > + mic_gain_get, mic_gain_put, ec_mic_gain_tlv)
> > +};
> > +
> > +static int enable_i2s(struct snd_soc_component *component, int enable)
> > +{
> > + struct ec_param_codec_i2s param;
> > + int ret;
> > +
> > + dev_dbg(component->dev, "%s set i2s to %u\n", __func__, enable);
> > +
> > + param.cmd = EC_CODEC_I2S_ENABLE;
> > + param.i2s_enable = enable;
> > +
> > + ret = ec_command(component, 0, EC_CMD_CODEC_I2S,
> > + (uint8_t *)&param, sizeof(param),
> > + NULL, 0);
> > + if (ret < 0) {
> > + dev_err(component->dev, "I2S enable %d command returned 0x%x\n",
> > + enable, ret);
> > + return -EINVAL;
> > + }
> > + return 0;
> > +}
> > +
> > +static int cros_ec_i2s_enable_event(struct snd_soc_dapm_widget *w,
> > + struct snd_kcontrol *kcontrol, int event)
> > +{
> > + struct snd_soc_component *component = snd_soc_dapm_to_component(
> > + w->dapm);
> > +
> > + dev_dbg(component->dev, "%s enter\n", __func__);
> > +
> > + switch (event) {
> > +
> > + case SND_SOC_DAPM_PRE_PMU:
> > + dev_dbg(component->dev,
> > + "%s got SND_SOC_DAPM_PRE_PMU event\n", __func__);
> > + return enable_i2s(component, 1);
> > +
> > + case SND_SOC_DAPM_PRE_PMD:
> > + dev_dbg(component->dev,
> > + "%s got SND_SOC_DAPM_PRE_PMD event\n", __func__);
> > + return enable_i2s(component, 0);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * The goal of this DAPM route is to turn on/off I2S using EC
> > + * host command when capture stream is started/stopped.
> > + */
> > +static const struct snd_soc_dapm_widget cros_ec_dapm_widgets[] = {
> > + SND_SOC_DAPM_INPUT("DMIC"),
> > +
> > + /*
> > + * Control EC to enable/disable I2S.
> > + */
> > + SND_SOC_DAPM_SUPPLY("I2S Enable", SND_SOC_NOPM,
> > + 0, 0, cros_ec_i2s_enable_event,
> > + SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_PRE_PMD),
> > +
> > + SND_SOC_DAPM_AIF_OUT("I2STX", "I2S Capture", 0, SND_SOC_NOPM, 0, 0),
> > +};
> > +
> > +static const struct snd_soc_dapm_route cros_ec_dapm_routes[] = {
> > + { "I2STX", NULL, "DMIC" },
> > + { "I2STX", NULL, "I2S Enable" },
> > +};
> > +
> > +
>
> nit: Please don't use multiple blank lines.
>

Fixed in v2.

> > +static const struct snd_soc_component_driver cros_ec_component_driver = {
> > + .controls = cros_ec_snd_controls,
> > + .num_controls = ARRAY_SIZE(cros_ec_snd_controls),
> > + .dapm_widgets = cros_ec_dapm_widgets,
> > + .num_dapm_widgets = ARRAY_SIZE(cros_ec_dapm_widgets),
> > + .dapm_routes = cros_ec_dapm_routes,
> > + .num_dapm_routes = ARRAY_SIZE(cros_ec_dapm_routes),
> > +};
> > +
> > +/*
> > + * Platform device and platform driver fro cros-ec-codec.
> > + */
> > +static int cros_ec_codec_platform_probe(struct platform_device *pd)
> > +{
> > + struct device *dev = &pd->dev;
> > + struct cros_ec_device *ec_device = dev_get_drvdata(pd->dev.parent);
> > + struct cros_ec_codec_data *codec_data;
> > + int rc;
> > +
> > + dev_dbg(dev, "%s start\n", __func__);
>
> Remove the debug trace.
>

Fixed in v2.

> > +
> > + /*
> > + * If the parent ec device has not been probed yet, defer the probe.
> > + */
> > + if (ec_device == NULL) {
> > + dev_dbg(dev, "No EC device found yet.\n");
> > + return -EPROBE_DEFER;
> > + }
>
> I think this check is unnecessary. The parent (mfd) will instantiate
> this driver so will be always there. Probably this is a copy from
> other cros-ec drivers that have also this unnecessary check. Did you
> find a use case where this is necessary?
>

Thank you for pointing this out.
In my use case, device is created from DTS, not MFD.
But I think you are right that parent will be created first so I
should remove this.
The place that I saw this usage was on cros_ec_keyb_probe for ACPI
flow only so it should be a different path.
https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/450838/6/drivers/input/keyboard/cros_ec_keyb.c#620

> > +
> > + codec_data = devm_kzalloc(dev, sizeof(struct cros_ec_codec_data),
> > + GFP_KERNEL);
> > + if (!codec_data)
> > + return -ENOMEM;
> > +
> > + codec_data->dev = dev;
> > + codec_data->ec_device = ec_device;
> > +
> > + platform_set_drvdata(pd, codec_data);
> > +
> > + rc = snd_soc_register_component(dev, &cros_ec_component_driver,
> > + cros_ec_dai, ARRAY_SIZE(cros_ec_dai));
> > +
> > + dev_dbg(dev, "%s done\n", __func__);
> > +
> > + return 0;
> > +}
> > +
> > +static int cros_ec_codec_platform_remove(struct platform_device *pd)
> > +{
> > + struct device *dev = &pd->dev;
> > +
> > + dev_dbg(dev, "%s\n", __func__);
> > +
> > + return 0;
> > +}
>
> I think you can remove this function it j only prints a message and as
> I said you can use trace tools for that.
>

Fixed in v2.

> > +
> > +#ifdef CONFIG_OF
> > +static const struct of_device_id cros_ec_codec_of_match[] = {
> > + { .compatible = "google,cros-ec-codec" },
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(of, cros_ec_codec_of_match);
> > +#endif
> > +
> > +static struct platform_driver cros_ec_codec_platform_driver = {
> > + .driver = {
> > + .name = DRV_NAME,
> > + .owner = THIS_MODULE,
>
> I think is not necessary set the .owner here.
>

Fixed in v2.

> > + .of_match_table = of_match_ptr(cros_ec_codec_of_match),
> > + },
> > + .probe = cros_ec_codec_platform_probe,
> > + .remove = cros_ec_codec_platform_remove,
>
> .remove can go away.
>

Fixed in v2.

> > +};
> > +
> > +module_platform_driver(cros_ec_codec_platform_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("Chrome EC codec driver");
>
> ChromeOS
>

Fixed in v2.

> > +MODULE_AUTHOR("Cheng-Yi Chiang <[email protected]>");
> > +MODULE_ALIAS("platform:" DRV_NAME);
> > diff --git a/sound/soc/codecs/cros_ec_codec.h b/sound/soc/codecs/cros_ec_codec.h
> > new file mode 100644
> > index 0000000000000..3a72e16a7ba65
> > --- /dev/null
> > +++ b/sound/soc/codecs/cros_ec_codec.h
> > @@ -0,0 +1,33 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * ChromeOS EC Codec
> > + *
> > + * Copyright 2018 Google, Inc
> > + *
> > + * This software is licensed under the terms of the GNU General Public
> > + * License version 2, as published by the Free Software Foundation, and
> > + * may be copied, distributed, and modified under those terms.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
>
> Remove the License boilerplate
>

Fixed in v2.

> > + */
> > +
> > +#ifndef __CROS_EC_CODEC_H
> > +#define __CROS_EC_CODEC_H
> > +
> > +/*
> > + * struct cros_ec_codec_data - ChromeOS EC codec driver data.
> > + *
> > + * @dev: Device structure used in sysfs.
> > + * @ec_device: cros_ec_device structure to talk to the physical device.
> > + * @component: Pointer to the component.
> > + */
>
> Please use the kernel documentation format here.
>

Fixed in v2.

> Thanks,
> Enric

Thanks a lot for the detailed review!

> > +struct cros_ec_codec_data {
> > + struct device *dev;
> > + struct cros_ec_device *ec_device;
> > + struct snd_soc_component *component;
> > +};
> > +
> > +#endif /* __CROS_EC_CODEC_H */
> > --
> > 2.20.0.rc0.387.gc7a69e6b6c-goog
> >
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